1. Field of the Invention
The present invention relates generally to carding machines and more specifically to an air guide plate for use at the intersection of the main cylinder and doffer.
2. Description of the Prior Art
In the processing of textile fibers through a card, accumulation of foreign matter at various points on the card interfere with the quality of textile material being produced and intefere with the operation of the carding equipment. Thus continuous cleaning of the equipment and maintenance is required to produce textile material of reliable quality. An area of major concern has been the build-up of foreign matter and waste materials at the intersection of the main carding cylinder and the doffer.
In order to remove the foreign matter from this area, U.S. Pat. No. 3,444,593 modifies the shrouds surrounding this area and uses a suction to remove the materials.
Another attempt to control the air at this intersection is described in U.S. Pat. No. 3,357,062 wherein the cover plates are redesigned so as to carry the foreign material to an outlet duct. This patent also discusses that the lower edge of the main cylinder cover plate is concave from the ends adjacent the card arching towards the center portion with respect to the width of the card. The purpose is to induce the direction of air away from the sides of the carding machine as it is moved towards the exit duct above the doffer. Though the concave configuration does produce a center directing air current, it also produces undesirable side effects in the material being carded.
Another attempt to prevent undesirable effects at the intersection of the main carding cylinder and doffer is disclosed in U.S. Pat. No. 3,362,047. Therein the snagging, ragged selvage or "snowballs", at the leading edge of the screen, are eliminated by beveling the corners of the leading edge of the main cylinder screen.
The prior art has provided many solutions for removing and preventing accumulation of foreign material and debris at the intersection of the main cylinder and the doffer and at the leading edge of the main cylinder screen. These devices, though attempting to solve the problem by bowing the plate, have lost control of the air currents and thereby introduced undesirable side effects including loss of efficiency. Thus there exists a need to efficiently prevent build-up of foreign material at the leading edge of the main cylinder screen and at the intersection of the main cylinder and doffer without introducing additional substantial side effects.